Tommaso de Giorgis

Insulin Resistance and Oxidative Stress in Children Born Small and Large for Gestational Age

OBJECTIVE: Our aim was to evaluate the effect of BW and obesity on oxidative stress and IR in prepubertal SGA and LGA children compared with appropriate-for-gestational-age (AGA) children. METHODS: We performed a cross-sectional study comparing oxidative stress and IR in 103 children categorized into 6 groups according to BW (26 SGA, 15 AGA, and 16 LGA normal-weight children) and obesity (15 SGA, 15 AGA, and 16 LGA obese children). Indexes of IR (HOMA-IR, G/I) and the marker of oxidative stress (urinary isoprostanes) were evaluated. RESULTS: Homeostasis Model Assessment was higher in both normal-weight SGA and LGA children than in normal-weight AGA children (all P ≤ .02). Furthermore, a difference was detected between obese SGA and obese LGA subjects compared with normal-weight SGA (all P ≤ .0007) and LGA (all P ≤ .01) children, respectively. The G/I ratio was lower in the 3 obese groups than normal-weight AGA (all P ≤ .009) and normal-weight SGA children (all P ≤ .02). Furthermore, a difference was detected between obese SGA and obese LGA children compared with normal-weight LGA children (all P ≤ .0002). Isoprostane levels were higher in both normal-weight SGA and LGA children than in normal-weight AGA children (all P ≤ .002). Moreover, both obese SGA and LGA children showed higher levels than obese AGA children (all P ≤ .01) and in comparison to the 3 normal-weight groups (all P ≤ .04). CONCLUSION: Increased IR and oxidative stress are already present in prepubertal normal-weight SGA and LGA children with a continuous alteration in relation to obesity, suggesting that BW and adiposity represent 2 independent risk factors for degenerative diseases.

Implications for kidney disease in obese children and adolescents

Increasing attention has been focused on the implications of obesity in adults on the development of kidney disease, but data on the obese pediatric population are lacking. The aim of this study was to investigate whether changes in various renal function indexes/markers, as expressed by the glomerular filtration rate [GFR, as estimated by the Schwartz formula (eGFR)], serum cystatin C (CysC) level, albumin excretion rate (AER), and modifications in nitric oxide (NO; an important modulator of renal function and morphology), urinary isoprostanes (markers of oxidative stress), and blood pressure (BP), can be detected in obese children and adolescents when compared to normal weight controls. Blood and urinary samples were collected to evaluate markers of renal function, serum and urinary NO, and urinary isoprostanes in 107 obese Caucasian subjects and 50 controls. Ambulatory BP monitoring (ABPM) was performed in all cases. Obesity was expressed by the body mass index standard deviation score (SDS-BMI), and insulin resistance by the homeostasis model assessment of insulin resistance (HOMA-IR). CysC and eGFR did not significantly differ between the two groups; AER was increased in obese children. CysC and GFR were related to HOMA-IR, and AER was related to HOMA-IR and SDS-BMI. Obese subjects had reduced NO levels and increased urinary isoprostanes and BP measurements; all three parameters were related to SDS-BMI and insulin resistance. ABPM showed an increased incidence of hypertension and non-dipping in the obese group. Based on our comparison of obese and nonobese children, we conclude that renal involvement is not an early clinically evident manifestation of adiposity in childhood, since no overt changes in eGFR and only a mild albuminuria were detected. A longer exposure to obesity is probably needed before renal function impairment appears.

Role of physical exercise in children and adolescents with diabetes mellitus

During the past 50 years several studies have underlined the central role of physical exercise in the management of patients with both type 1 and type 2 diabetes mellitus. The numerous benefits described in normal individuals who practise regular exercise have also been demonstrated in patients with diabetes who obtained significant physical and psychological advantages for the care of the underlying disease. Despite physical and psychological benefits, the occurrence of acute complications and some important effects on diabetes-related vascular complications may often discourage patients from participation in sports activities. However, even though adverse events may occur, exercise is still judged one of the most important components in the treatment of patients with diabetes. Thus, children, adolescents and young adults with diabetes must be educated on the metabolic changes occurring during physical activity in order to be able to acquire the ability to individually modulate their diet and insulin therapy before and after exercise. Appropriate education may allow a proper and correct approach to physical exercise.

Triglycerides-to-HDL ratio as a new marker of endothelial dysfunction in obese prepubertal children

OBJECTIVE To investigate whether there is an association of the triglyceride-to-HDL cholesterol (TG:HDL-C) ratio with cardiovascular risk factors and early signs of vascular damage in obese prepubertal children. DESIGN AND METHODS In 50 obese (27 boys, 7.8±1.4 years) and 37 normal-weight (20 boys; 7.3±1.5 years) prepubertal children, anthropometric measurements, oxidative stress markers (urinary isoprostanes (PGF2α (prostaglandin F2α)), soluble receptor for advanced glycation end-products (sRAGE)) and insulin sensitivity (homeostasis model assessment of insulin resistance (HOMA-IR) and whole-body insulin sensitivity index (WBISI)) were evaluated. Lipids profile was assessed and the TG:HDL-C ratio was calculated. In addition, high-resolution ultrasound was performed to assess carotid intima-media thickness (cIMT). RESULTS Obese children showed significantly higher values of the TG:HDL-C ratio (1.9±1.1 vs 1.2±0.6, P=0.002) compared with controls. After dividing the population in tertiles of the TG:HDL-C ratio (<1.04, 1.04-1.67, >1.67), cIMT (P=0.0003), and HOMA-IR (P=0.0001) progressively increased from the lower to the upper tertile, whereas WBISI (P=0.0003) and sRAGE (P=0.05) progressively decreased. In a regression model, the TG:HDL ratio was significantly and positively associated with cIMT (r=0.493; P=0.0005). A cutoff point for TG:HDL-C ratio of 1.12 had 81% sensitivity and 49% specificity in the identification of children with cIMT values in the upper quartile (Area under the curve values from receiver operating characteristic curves=0.633±0.065, P=0.045). CONCLUSION This study confirms the reliability of the TG:HDL-C ratio as a useful marker of cardiovascular risk. Interestingly, our results underline that the TG:HDL-C ratio is directly related with early signs of vascular damage already present in prepubertal children.

Progression of cardio-metabolic risk factors in subjects born small and large for gestational age.

Background Subjects born small (SGA) and large (LGA) for gestational age have an increased risk of cardio-metabolic alterations already during prepuberty. Nevertheless, the progression of their cardio-metabolic profile from childhood to adolescence has not been fully explored. Our aim was to assess potential changes in the cardio-metabolic profile from childhood to adolescence in subjects born SGA and LGA compared to those born appropriate (AGA) for gestational age. Methods This longitudinal study included 35 AGA, 24 SGA and 31 LGA subjects evaluated during childhood (mean age (±SD) 8.4±1.4 yr) and then re-assessed during adolescence (mean age 13.3±1.8 yr). BMI, blood pressure, insulin resistance (fasting insulin, HOMA-IR) and lipids were assessed. A cardio-metabolic risk z-score was applied and this consisted in calculating the sum of sex-specific z-scores for BMI, blood pressure, HOMA-IR, triglycerides and triglycerides:high-density lipoprotein cholesterol ratio. Results Fasting insulin and HOMA-IR were higher in SGA and LGA than AGA subjects both during childhood (all P<0.01) and adolescence (all P<0.01). Similarly, the clustered cardio-metabolic risk score was higher in SGA and LGA than AGA children (both P<0.05), and these differences among groups increased during adolescence (both P<0.05). Of note, a progression of the clustered cardio-metabolic risk score was observed from childhood to adolescence within SGA and within LGA subjects (both P<0.05). Conclusions SGA and LGA subjects showed an adverse cardio-metabolic profile during childhood when compared to AGA peers, with a worsening of this profile during adolescence. These findings indicate an overtime progression of insulin resistance and overall estimated cardiovascular risk from childhood to adolescence in SGA and LGA populations.

What Is the Significance of Soluble and Endogenous Secretory Receptor for Advanced Glycation End Products in Liver Steatosis in Obese Prepubertal Children

The endogenous secretory receptor for advanced glycation end products (esRAGE) and soluble RAGE (sRAGE) have been shown in human plasma and have emerged as reliable biomarkers of several pathological conditions, including insulin resistance and liver injury. We examined esRAGE and sRAGE levels in obese prepubertal children with and without liver steatosis. esRAGE and sRAGE levels were significantly lower in obese prepubertal children affected by liver steatosis and were independently related to liver steatosis. These findings suggest that AGE-RAGE pathway plays an independent role in the development of liver injury already present in this age group.

Weight gain and insulin resistance in children treated with valproate: the influence of time.

This study was undertaken in 2 parts to investigate the relationship between body size and insulin resistance during treatment with valproic acid in children. The cross-sectional part revealed differences in terms of body size and homeostasis model assessment of insulin resistance, which were higher in the group on medication. The longitudinal part showed a major increase in body size and insulin resistance during the first year of therapy. There was a subsequent decrease in insulin resistance in association with the rise of body size, however with a trend to level off. These results might be helpful to enhance the knowledge of valproic acid action on both insulin resistance and weight gain, allowing to plan appropriate approach for the prevention of the consequences of the treatment with valproic acid.

The Reciprocal Influences of Asthma and Obesity on Lung Function Testing, AHR, and Airway Inflammation in Prepubertal Children

Although asthma and obesity are among the major chronic disorders their reciprocal or independent influences on lung function testing, airways hyperresponsiveness (AHR) and bronchial inflammation has not been completely elucidated.

The possible role of esRAGE and sRAGE in the natural history of diabetic nephropathy in childhood

The advanced glycation end products/receptor for advanced glycation end products (AGE–RAGE) pathway is a key mediator of glomerular changes in type 1 diabetes. We evaluated endogenous secretory (es)RAGE and soluble (s)RAGE concentrations in 64 pre-pubertal and pubertal normoalbuminuric patients with type 1 diabetes and compared the values with those of 62 controls matched for age, gender and Tanner pubertal stages. We also explored the possible association of their concentrations with early signs of diabetic nephropathy, defined as changes in kidney volume and estimated glomerular filtration rate (eGFR). Significantly lower concentrations of both esRAGE and sRAGE were documented in pre-pubertal (p = 0.003 and p = 0.001) and pubertal (p = 0.002 and p = 0.001) subjects with type 1 diabetes than in the controls. In both groups of patients with type 1 diabetes, the eGFR (pre-pubertal p = 0.01 and pubertal p = 0.01) and the mean value of kidney volume adjusted for body surface (pre-pubertal p = 0.003 and pubertal p = 0.002) were higher than those of the controls. The regression analysis showed an inverse relationship between esRAGE and body surface-adjusted mean kidney volume (p = 0.0004, r = −0.503). esRAGE and sRAGE concentrations were lower in normoalbuminuric youths with type 1 diabetes than in their healthy peers. The inverse association between esRAGE levels and early kidney alterations suggests a potential role of esRAGE in diabetic nephropathy.

Serum Levels of Receptors for Advanced Glycation End Products in Normal-Weight and Obese Children Born Small and Large for Gestational Age

OBJECTIVE To assess potential alterations in soluble and endogenous secretory receptors for advanced glycation end products (sRAGE and esRAGE) in normal-weight (NW) and obese (Ob) children born small (SGA) and large (LGA) compared with appropriate for gestational age (AGA) subjects and to explore if birth weight (BW), insulin resistance (IR), and obesity represent independent risk factors. RESEARCH DESIGN AND METHODS We categorized 130 prepubertal children into six groups according to BW and obesity and evaluated sRAGE, esRAGE, and homeostasis model assessment of IR. RESULTS sRAGE and esRAGE were lower in Ob SGA and LGA children than Ob AGA subjects (all P < 0.05), and in NW SGA and LGA children than NW AGA subjects (all P < 0.05). Interestingly, BW and IR were significantly and independently related to RAGE. CONCLUSIONS sRAGE and esRAGE are decreased in SGA and LGA children, and BW and IR seem to play an important role in the reduction of RAGE.